1. Technical Field of the Invention
The present invention relates to a condenser, a power plant and an operation method thereof.
2. Description of Prior Arts
In a fossil power plant, nuclear power plant, or the like, steam exhausted from a steam turbine is cooled by a condenser using sea water as cooling water. However, since sea water is used as cooling water in the condenser as mentioned above, sea water has become a cause of corrosion or the like of structural apparatus and piping, etc. of the power plant when the sea water flowed into the condenser, so that it is necessary to monitor always water quality inside the system to find whether or not sea water leaks into the interior of the condenser. If the water quality inside the system exceeds a set value because of leakage of sea water into the interior of the condenser, a signal is issued from a detection part, and an alarm is generated on a monitor, operation panel, etc. An operator has received the alarm, identified a position and degree of the leakage, and judged whether or not the plant operation was stopped or continued according to the result, and they were operated manually.
Further, as an example of conventional water quality monitors, there are proposals disclosed in JP A 3-248030, JP A 6-11406 and JP A 5-264393.
For example, JP A 3-248030 discloses an apparatus in which a condenser hot well is divided into a first water chamber and a second water chamber by a partition wall, an electric conductivity measuring apparatus is provided in each water chamber and it is monitored whether or not an absolute value of difference between two electric conductivities is within an upper limit value. JP A 6-11406 discloses an apparatus in which the conductivity of a sample liquid which is taken from a condenser and deaerated by a gas-permeable film and the conductivity of a sample liquid taken from a recirculating water delivered by a condenser pump and deaerated in the similar manner are compared, whereby mixing of sea water is judged. Further, JP A 5-264393 discloses an apparatus in which water quality is detected in a plurality of positions of piping of a condenser system, leakage is judged at each position and total diagnosis of those leakage conditions are classified in steps and displayed.
However, the apparatus disclosed in JP A 3-248030, JP A 6-11406 and JP A 5-264393 each are provided with a detection point for taking out detection water in a condenser outlet through which the whole condensate passes, on the downstream side of a condenser pump for delivering condensate in the condenser, or in piping connecting from the condenser to a steam generator. However, in the case where the detection point is provided in the condenser outlet or on the downstream side of the condenser pump for delivering condensate in the condenser, or in the piping connecting the condenser to the steam generator, a time is taken until sea water leakage is detected, whereby there is the possibility that the water mixed with sea water is flowed out from the condenser even if the plant is stopped or a feed water system is closed after the detection of sea water leakage, and that the sea water-mixed water flows into the steam generator and steam turbine since the sea water-mixed water is delivered by the condenser pump.
An object of the present invention is to provide a condenser, power plant equipment and operation method thereof, in which leakage of cooling water is detected early and it is suppressed that water mixed with sea water due to the sea water leakage or the like flows into a steam generator and a steam turbine.
The present invention provides the following condenser:
That is, a condenser of the present invention condenses steam flowed therein from a turbine and supplies the condensate into a feed water system leading to a steam generator, and comprises a steam condensing zone having a heat exchanger tube bundle and condensing steam and a hot well zone allowing the condensate condensed in the steam condensing zone to stay, wherein
a plurality of detectors for detecting the quality of the condensate and/or detection ports taking out the condensate are provided in the hot well zone, a control valve adjusting supply of the condensate to be supplied from the condenser to the feed water system on the basis of water quality detection values detected from the plurality of detectors and/or detection ports is provided on the feed water system, and a make-up water system supplying make-up water to said feed water system on the downstream side of said control valve is provided.
Further, a condenser according to the present invention condenses steam flowed therein from a turbine and supplies the condensate into a feed water system leading to a steam generator, and
the condenser comprises a steam condensing zone having a heat exchanger tube bundle and condensing steam and a hot well zone allowing the condensate condensed in the steam condensing zone to stay there,
a plurality of detectors for detecting the quality of the condensate and/or detection ports taking out the condensate are provided in the hot well zone, and
a chemical injecting system supplying chemical dilution water to the feed water system on the basis of water quality detection values detected from the plurality of detectors and/or detection ports is provided.
Preferably, the detectors and/or detection ports are arranged separately from each other in a course leading from an upstream side of the hot well zone into which the condensate flows from the steam condensing zone to a downstream side of the hot well zone from which the condensate flows out into the feed water system, and a judging device for comparing respective water quality values detected from the detectors and/or detection ports, and judging sea water leakage when a water quality detection value detected from the detectors and/or detection ports on the upstream side represents to be lower in water quality detection value than a water quality detection value detected from the detectors and/or detection ports on the downstream side.
The present invention provides the following power plant equipment:
That is, a power plant equipment according to the present invention comprises a steam generator generating steam, a steam turbine driven by the steam generated in the steam generator, a condenser condensing the steam exhausted from the steam turbine into condensate, and a feed water system supplying the condensate to the steam generator,
wherein the condenser comprises a steam condensing zone having a heat exchanger tube bundle and condensing steam and a hot well zone allowing the condensate condensed in the steam condensing zone to stay,
a plurality of detectors for detecting the quality of the condensate and/or detection ports taking out the condensate are provided in the hot well zone,
a control valve adjusting supply of the condensate to be supplied from the condenser to the feed water system on the basis of a water quality detection value detected from the plurality of detectors and/or detection ports is provided on the feed water system, and
a make-up water system communicating with the feed water system on the downstream side of the control valve and supplying make-up water is provided.
Further, a power plant equipment according to the present invention comprises a steam generator generating steam, a steam turbine driven by the steam generated in the steam generator, a condenser condensing the steam exhausted from the steam turbine into condensate, and a feed water system supplying the condensate to the steam generator,
wherein the condenser comprises a steam condensing zone having a heat exchanger tube bundle and condensing steam and a hot well zone allowing the condensate condensed in the steam condensing zone to stay,
a plurality of detectors for detecting the quality of the condensate and/or detection ports taking out the condensate are provided in the hot well zone, and
a chemical injecting system supplying chemical dilution water to the feed water system on the basis of the water quality detection values detected from the detectors and/or detection ports is provided.
Preferably, the above-mentioned power plant equipment is provided with a make-up water tank having make-up water stored therein and an apparatus for supplying the make-up water stored in the make-up water tank to the condenser or the feed water system.
Further, preferably, the above-mentioned power plant equipment is provided with a chemical storage tank storing chemical dilution water for neutralizing the condensate mixed with sea water, and a chemical dilution water supplying apparatus supplying the chemical dilution water stored in the chemical storage tank to the condenser or the feed water system.
Further, preferably, there is provided a discharging system for discharging, out of the feed water system, condensate on the upstream side of a control valve controlling a flow rate of the condensate to be supplied to the steam generator.
The present invention provides the following operation method of power plant equipment:
That is, an operation method of a power plant equipment comprising a steam generator generating steam, a steam turbine driven by the steam generated in the steam generator, a condenser condensing the steam exhausted from the steam turbine into condensate, and a feed water system supplying the condensate to the steam generator, comprises the steps:
detecting the water quality of condensate at a plurality of detecting points in a hot well zone allowing the condensate condensed inside the condenser to stay,
judging sea water leakage on the basis of the detection values of water quality detected at the plurality of detecting points,
adjusting supply of the condensate to be supplied from the condenser to the feed water system by operating a control valve arranged in the feed water system when judged to be sea water leakage, and
supplying make-up water to the feed water system from a make-up water system communicating with the feed water system on the downstream side of the control valve.
Further, a method of operating a power plant equipment according to the present invention, which equipment comprises a steam generator generating steam, a steam turbine driven by the steam generated in the steam generator, a condenser condensing the steam exhausted from the steam turbine into condensate, and a feed water system supplying the condensate to the steam generator, comprises the steps:
detecting the water quality of condensate at a plurality of detecting points in a hot well zone allowing the condensate condensed inside the condenser to stay,
judging sea water leakage on the basis of detection values of water quality detected at the plurality of detecting points, and
supplying chemical or chemical dilution water to the feed water system when sea water leakage is judged.
Preferably, in a method of operating the above-mentioned power plant equipment, the condensate mixed with sea water is discharged out of the feed water system in a middle flow course from the condenser to the steam generator when judged to be sea water leakage.
Further preferably, the method comprises:
detecting the water quality of condensate at separate positions in a course from an upstream side of a hot well zone allowing the condensate condensed inside the condenser to stay to a downstream side of the hot well zone from which the condensate flows out into the feed water system,
comparing respective water quality values detected at the detecting points, and
judging sea water leakage when a water quality detection value detected at one of the detecting points on the upstream side represents to be lower in water quality than a water quality detection value detected at one of the detecting points on the downstream side.
Here, chemical may be medicine as long as it has a function of neutralizing sea water.